1. Field of the Invention
The present invention relates to a stethoscopic apparatus, and more particularly to a stethoscope equipped with a plurality of chestpieces to be chosen for use by a doctor which are capable of highly resoluting the heart sounds detected.
2. Brief Description of the Prior Art
Conventional stethoscopes are indispensable medical instruments enabling doctors to diagnose the diseases of their patients. A typical conventional stethoscope is shown in FIG. 1 generally consisting of an open bell or Ford chestpiece 1, a closed diaphragm or Bowles chestpiece 2, a tubing 3 for the transmission of the heart sounds detected by the chestpieces, and a pair of headsets 4 and eartips 5. Several disadvantages related especially to the chestpieces were found in the conventional stethoscopes.
When a doctor uses a conventional stethoscope, he has to push the Ford chestpiece 1 against the body of the patient so that an airtight sealed resonance chamber may be formed for the purpose of detecting low pitch body sounds such as third and fourth heart sounds, mitral and tricuspid murmurs, etc.. However, a conventional Ford chestpiece does not enable the easy formation of the afore said resonance chamber especially when the patient is dressed or wrapped in bandages. Therefore, the sounds detected by the conventional Ford chestpiece are usually incomplete, thus affecting seriously the accuracy of the diagnosis.
A conventional Bowles chestpiece 2 is usually equipped with a diaphragm for the detection of those body sounds of higher frequencies such as first and second heart sounds, the ejection sounds and clicks, the opening snap of mitral or tricuspid stenosis, the murmurs of aortic or pulmonary valve regurgitation, the murmurs of interventricular septal defects, etc.. It has been noted that when the Bowles chestpiece is placed against the body of a patient, significant tension will be applied to the soft tissue beneath the diaphragm of the chestpiece. Therefore, the higher frequency portion of the vibration wave of those visceras is easily conducted to the body surface. This is the reason why moderate pressure must be exerted onto the body surface while using the Bowles chestpiece.
For better contact feeling with a patient's body, the conventional Ford chestpiece 1 is equipped with an O-ring 1a made of a soft material. It is easily understood that the O-ring will effect the body contact situation.
The conventional Bowles chestpiece includes a fixation rim 2b for the diaphragm 2a which is made of either metal, rubber or plastic. There is usually a height difference between the diaphragm 2a and the fixation rim 2b. Therefore it is relatively difficult to make ideal contact between the chestpiece and the body's surface for receiving the vibration waves from the viscera via said body's surface and diaphragm. Moreover, on account of the existence of the conventional indispensible fixation rim, the free vibration of the diaphragm in accordance with the vibration wave of the viscera and the body's surface will be highly limited by the fixation rim. Therefore, there is a definite defect in the transformation of the visceral vibration waves into sound waves transmitted via the body's surface, the diaphragm, and the vibration air chamber under the diaphragm. Besides, given the fact that male threads and female threads must be provided on the chestpiece and the rim respectively for the installation of the diaphragm, the overall structure of the chestpieces is complicated.
A conventional stethoscope includes only two chestpieces. Doctors have no further choice except to use the handy Ford and Bowles chestpieces on the stethoscope. This limits the scope of use of conventional stethoscopes.
A multi-functional radio/wire stethoscopic apparatus was disclosed in U.S. Pat. No. 4,723,555 issued to the same inventor as of this application. This patent is mentioned and incorporated here for the purpose of better understanding the present invention and also for the reference of those portions of the structure identical to the same in the present invention.